Surface Condenser Quiz and Flashcards: Design and Efficiency

Study Notes

Surface Condensers (Non-Mixing Type Condensers)

Use indirect heat transfer, preventing contamination and allowing condensate reuse.
Efficient tube arrangement leads to steam condensation for various applications, despite initial cost challenges.

Requirements of a Good Surface Condenser

Steam should enter the condenser with least possible resistance for easy flow.
Steam should be well distributed in the vessel with minimum pressure drop.
Circulating cooling water should flow through tubes with least friction.
Rise in temperature of cooling water should be limited to 10°C for better thermal efficiency.
No undercooling of the condensate, steam should lose only its latent heat to the circulating water.
Tubes should be made of high thermal conductivity material.
No leakage of air from the condenser.

Jet Condensers (Mixing Type Condensers)

Direct contact between exhaust steam and cooling water.
Temperature of the condensate matches the cooling water leaving the condenser.
Heat transfer occurs through direct conduction between steam and water.
Cooling water impurities limit condensate reuse, causing loss and higher pump power.

Types of Jet Condensers

Low-level jet condensers: parallel flow type and counter flow type.
High-level jet condensers: use gravity to direct condensate and cooling water into the hot well.

Steam Condenser

Device in which exhaust steam from the steam turbine is condensed by means of cooling waters.
Condensation done by removing heat from the exhaust steam using circulating water.

Advantages of a Condenser in a Steam Power Plant

Increases efficiency of the power plant due to increased enthalpy.
Reduces back pressure of the steam, resulting in more work output.
Reduces temperature of the exhaust steam, resulting in more work output.
Condensed steam can be reused as feed water for boiler, reducing cost of power generation.
Temperature of the condensate is higher than that of fresh water, reducing heat supplied per Kg of steam produced.

Other Important Functions of Condensers

Create a vacuum by condensing steam.
Remove dissolved non-condensable gases from the condensate.
Provide a leak-tight barrier between the high-grade condensate and the untreated cooling water.
Provide leak-tight barrier against air ingress, preventing excess back pressure on the turbine.

Elements of a Steam Condensing Plant

Condenser
Condensate extraction pump
Air extraction pump
Hot well
Boiler feed pump
Condenser cooling water pump
Make-up water pump
Cooling tower or spray pond
Relief valve

Description

Explore the design features and efficiency of surface condensers, known for preventing contamination and enabling condensate reuse. Learn about the requirements for optimal steam condensation within the vessel.